Introduction Momentum is a property of moving objects

Introduction • Momentum… – is a property of moving objects – depends on mass and velocity • p = mv • kg·m/s – is a vector • Direction is always same as velocity

Examples • What is the momentum of a 2, 000 kilogram car traveling with a speed of 5 meters per second? p = mv p = (2, 000 kg)(5 m/s) p = 10, 000 kg·m/s • What would its momentum be if it was traveling at 10 meters per second? p = mv p = (2, 000 kg)(10 m/s) p = 20, 000 kg·m/s

Comparing Momentum Which has more momentum? Neither Player 2, 000 at 5 m/s 30 kg kgcar soccer player at 2 m/s kg bus at 1 m/s 6010, 000 kg soccer ref at 0 m/s The. Both player havehas a momentum of 10, 000 of 60 kg·m/s!!! while the ref has none!!!

Impulse • Impulse… – is a change in momentum – Encountered when changes in motion occur

Impulse - Starting A 60 kilogram drag racer accelerates from 0 to 330 mph (148 meters per second) in 5 seconds. What is. What the. How change is the average in momentum force exerted encountered on theby racer the racer? many g’s does he/she experience? during this acceleration? F =mΔv mg JJg== Ft Fg = (60 kg)(9. 81 m/s 2) =kg)(148 588. 6 Nm/s) gkg·m/s J 8880 = F(60 = F(5 s) =F 8880 = 1776 #J of g’s = kg·m/s FAN/ Fg 1776 N / 588. 6 N = 3. 0 g’s

Impulse - Stopping A 55 kilogram human cannonball flies into a waiting net. He hits the net with an initial speed of 15 meters per second. The net stops his motion within 0. 5 seconds. is the average force exerted on theby person What is. What the change in momentum encountered the person? Howduring many g’s does he experience? this deceleration? JFJ= mΔv Ft mg g= Fg = (55 kg)(9. 81 m/s 2) 825 J =Fkg·m/s (55 kg)(15 = F(0. 5 N m/s)s) g = 539. 55 J =F 825 = 1650 kg·m/s N # of g’s = FA / Fg 1650 N / 539. 55 N = 3. 1 g’s